Ecosystems and material cycles

Question 1

What are the 5 steps of eutrophication?

Answer 1

1. Fertilisers enter the water, adding excess nitrates
2. The excess nitrates cause algae to grow quickly, blocking out light
3. Plants can’t photosynthesise, die and decompose
4. With more food available, microorganisms that feed on decomposing plants increase and use up all oxygen
5. Organisms can’t respire and die

Question 2

What does individual mean in terms of an ecosystem?

Answer 2

A single organism

Question 3

What does population mean in terms of an ecosystem?

Answer 3

All the organisms of one species in a habitat

Question 4

What does community mean in terms of an ecosystem?

Answer 4

All the organisms of different species living in a habitat

Question 5

What does abiotic mean?

Answer 5

A non living factor

Eg. Temperature, light intensity

Question 6

What does biotic mean?

Answer 6

A living factor

Eg. Competition, predation

Question 7

What does interdependent mean?

Answer 7

Describes how individual species are dependent on each other for resources

Question 8

What is biodiversity?

Answer 8

The variety of living organisms in an ecosystem

Question 9

What is an ecosystem?

Answer 9

A community of organisms along with all the non living conditions

Question 10

What are the 3 steps of using a quadrat?

Answer 10

Put it on the grass

Count/identify species

Multiply the numbers

Question 11

How do you multiply using a quadrat?

Answer 11

Work out the mean per metres squared, then multiply the mean by the total area of the habitat

Question 12

What are the 3 steps to using a belt transect?

Answer 12

1. Mark a line in desired area
2. Collect data using multiple quadrats lined up
3. Repeat several times and find mean

Question 13

What is the advantage of using a belt transect?

Answer 13

A clear gradual change can show how abundance changes with it and the effect of the factor on the different plant species

Question 14

What is the disadvantage of using the belt transect?

Answer 14

Species which don’t fall on the line or in the belt may be missed and therefore the sample is not representative

Question 15

What are the positive human impacts on biodiversity?

Answer 15

Reforestation

Conservation schemes

Question 16

What are the negative human impacts on biodiversity?

Answer 16

Eutrophication

Fish farming

Question 17

How can humans reduce biodiversity?

Answer 17

No indigenous species

Question 18

What are the benefits of reducing biodiversity?(4)

Answer 18

• protects human food supply
• minimal damage to food chains
• future medicines
• ecotourism

Question 19

What are the 7 steps of the water cycle?

Answer 19

Condensation
Precipitation
Evaporation
Transpiration
Surface run off
Percolation
Groundwater run off

Question 20

What is condensation in the water cycle?

Answer 20

When watervapour creates a cloud

Question 21

What is precipitation in the water cycle?

Answer 21

Rain

Question 22

What is evaporation in the water cycle?

Answer 22

Water turns into a gas

Question 23

What is transpiration in the water cycle?

Answer 23

Watervapour removed through plants

Question 24

What is surface run off in the water cycle?

Answer 24

Water runs off ground

Question 25

What is percolation in the water cycle?

Answer 25

Water moves into ground

Question 26

What is groundwater run off in the water cycle?

Answer 26

Water goes underground

Question 27

What are the 7 steps of the carbon cycle?

Answer 27

``` Photosynthesis Food chains Animal respiration Plant respiration Combustion Death Respiration of composers ```

Question 28

How do plants take in nitrates? (4)

Answer 28

- active transport - through root hair cells - low to high (soil to root hair cell) - using energy for respiration

Question 29

What can lightning do in the nitrogen cycle?

Answer 29

Make oxygen react with nitrogen to make nitrates

Question 30

What do fertilisers do to the nitrogen cycle?

Answer 30

Increase crop yield

Question 31

What does nitrogen fixing bacteria do?

Answer 31

Converts nitrogen gas into nitrates

Question 32

Where does nitrogen fixing bacteria live?

Answer 32

Soil/root nodules/legumes

Question 33

Why is the nitrogen cycle mutualistic?

Answer 33

Bacteria gets glucose Plant gets nitrates

Question 34

What do food chains do in the nitrogen cycle?

Answer 34

Proteins/amino acids from organisms used by consumers to make more proteins

Question 35

What do decomposer bacteria do in the nitrogen cycle?

Answer 35

Turn ammonia into nitrates

Question 36

What does nitrifying bacteria do in the nitrogen cycle?

Answer 36

Break down protein from dead plants into ammonia

Question 37

What does denitrifying bacteria do in the nitrogen cycle?

Answer 37

Turn nitrates from soil into nitrogen gas in the air

Question 38

What is crop rotation?

Answer 38

Different nitrogen fixing crops are grown each year in a cycle putting nitrates into the soil for the crop to use the following year

Question 39

How do fertilisers increase the amount of nitrates in the soil?

Answer 39

They recycle nutrients and return them to the soil through decomposition